Oscillator circuitry is employed for radio frequency applications of many kinds, including cellular telephones, data communications networks, cordless telephones, local area networks (LAN), wireless LAN systems, wireless wide are networks (WAN), and private branch exchange (PBX) applications, for example. Oscillator circuitry operates stably and linearly within the limits of supply voltage rails.
To maximize gain while operating within the linear region of the oscillator circuitry requires setting the resonant operation of oscillator circuitry to operate substantially fully within the positive and negative voltage rails of the supply, without exceeding these limits to any substantial extent. This limits the amount of distortion suffered during oscillator operation. As is well-known, the resonator circuit of an oscillator circuitry can be characterized according to its "Q" value.
It is accordingly desirable to develop a universal integrated circuit or IC that would accept adaptively any of a number of different resonator circuits having any of a range of particular characteristics.
At present, the designer for an oscillator circuit provides for manual setting of transistor bias levels which permit exact mating with a particular resonator circuit. As a result, after fabrication, the particular oscillator circuit designed mates well with the particular resonator for which it has been designed and correctly sets the bias values for the anticipated resonator with which it has been designed to operate, but generally is incapable of adaptive coordination with other resonators which may be substituted for the originally anticipated resonator.